    
    Example use:
 
+   ```clj
    (def my-interceptor
      (->interceptor                
        :id     :my-interceptor       

       :after  (fn [context]                         ;; you normally want to change :effects
                 (let [db (get-effect context :db)]  ;; (get-in context [:effects :db])
                   (assoc-effect context :http-ajax {...}])))))

   "
  [& {:as m :keys [id before after]}]


;; -- interceptors ------------------------------------------------------------

(def debug
  "An interceptor which logs/instruments an event handler's actions to
  `js/console.debug`. See examples/todomvc/src/events.cljs for use.

  Output includes:
   
  1. the event vector
  2. a `clojure.data/diff` of db, before vs after, which shows
     the changes caused by the event handler. To understand the output,
